Diazotype and like photo-copying apparatus



Feb. 13,1962 J. G. B HALDEN 3,020,818

DIAZOTYPE AND LIKE PHOTO-COPYING APPARATUS Filed April 20, 1959 3 Sheets-Sheet 1 1962 J. G. s. HALDEN I 3,020,818

DIAZOTYPE AND LIKE PHOTO-COPYING APPARATUS Filed April 20, 1959 s Sheets-Sheet 2 Feb. 13, 1962 J. G. B. HALDEN 3,020,818

DIAZOTYPE AND LIKE PHOTO-COPYING APPARATUS Filed April 20, 1959 3 Sheets-Sheet 3 mm WW United States Patent Ofiice 3,020,818 Patented Feb. 13, 1962 3,020,818 DIAZOTYPE AND LIKE PHOTO-COPYING APPARATUS Joseph Gerald Brocton Halden, Loughton, England, as-

signor to Ozalid Company Limited, Loughton, England, a British company Filed Apr. 20, 1959, Ser. No. 807,567 Claims priority, application Great Britain Apr. 24, 1958 Claims. (Cl. 95-89) fractional variation in length of each individual belt of the system and/or the possible fractional differences in diameter along the length of the supporting and/or driving rollers. In the case of a wide sealing belt, tracking difiicult'ies may arise from various factors such as unequal wear or stretching of the belt across its width, or

The invention relates to diazotype and like photocopying apparatus of the kind (hereinafter referred to as the kind described) in which sheet material is conveyed through the apparatus by means employing one or more flexible conveyor belts.

Apparatus of this kind commonly comprises either two sections (i.e. an exposure or printing section and a developing section) or three sections (i.e. an exposure section, a separating section and a developing section). In the printing section of one form of the apparatus sensitised sheet material with an original sheet to be copied is fed past an exposure station by means of the moving endless conveyor belts, the belts being lapped around a part of the periphery of a transparent printing cylinder and the movement of the belts carrying the light sensitive material and the original around the printing cylinder. There is usually a plurality of narrow conveyor belts of canvas or other flexible material spaced apart across the width of the machine, the belts being taken around appropriately disposed rollers.

After the exposure of the light sensitive material the original and exposed material may be separated by hand or, when there is a separating section, they pass to the separating section, which may comprise suction boxes, pick oif fingers and conveyor belts of the kind above indicated, where the exposed material is separated from the original, the latter being delivered outside the machine (e.g. on to a tray or the like) while the former is conveyed to the developing section.

The developing section may comprise a developing tank or chamber in which aqueous ammonia solution is vaporised, or to which ammonia vapour is delivered, the vapours emanating through, for instance, a perforated or porous portion of a wall of the said tank or chamber over which the exposed material is traversed by means of a moving endless belt or blanket, usually of rubber, which not only causes the material to travel over the perforated or porous wall area, but also provides a seal around the area and prevents the vapours escaping into the surrounding atmosphere. With such sealing belts or blankets little difiiculty is experienced in effecting sealing transversely across the width of the area, both at the beginning and the end of the perforated or porous area but it is not always easy to secure adequate sealing along the sides, i.e. along the edges of the area in the direction of movement of the belt or blanket.

One of the main reasons why this difficulty in providing adequate sealing along the side edges of the area arises is due to the flexibility and length of the sealing belt or blanket which makes it diflicult to ensure that the said belt or blanket lies tightly in sealing relationship with the tank or chamber at the sides of the area and over the entire length thereof.

In addition to the difficulty of ensuring adequate edge sealing of the sealing belt or blanket certain difliculties regarding the correct tracking of the Wide sealing belt or blanket and of the narrow conveyor belts used in the other section or sections of the machine may also be encountered in practice.

Thus in the case of a plurality of narrow endless belts spaced acrossthe width of their supporting and/or driving rollers, tracking difficulties are due mainly to the supporting rollers which are not exactly parallel or not of exactly constant diameter along their length.

In certain types of diazotype apparatus the developing tank or chamber instead of having a fixed perforated surface over the area aforesaid from which developing vapours emanate, is provided with an aperture which is closed, or substantially closed, by a moving endless belt or blanket of a foraminous or vapour passing nature, disposed internally of the tank or chamber and travelling around rollers also disposed internally of the tank or chamber.

These internal conveyor belts or blankets suffer from the same tracking difficulties as the other conveying and/or sealing belts of the apparatus.

The present invention is concerned with improvements in the conveyor belts of apparatus of the kind described designed to overcome or reduce either or both of the difiiculties of sealing and tracking as discussed above.

The invention provides diazotype or like photocopying apparatus of the kind described characterised in that the belt, or at least one belt when there are more than one, is provided with at least one supporting or stiffening rib or equivalent belt-like member extending longitudinally around the belt.

When the conveyor belt is also employed as a sealing belt or blanket to prevent escape of a developing vapour, the belt being of substantial width, it preferably has a rib or belt-like member as aforesaid, adjacent each side edge. Likewise when the conveyor belt is of porous material and serves to permit vapour used for development to pass through the belt to the sheet material being carried thereby, the belt in this case also being of substantial width, it preferably has a rib or belt-like member as aforesaid, adjacent each side edge.

In the case where, as in a printing or separating section, there are several belts (e.g. ofrubber) arranged to travel alongside one another in spaced apart relation, each conveyor belt may have a rib or belt-like member as aforesaid, for example, at the centre of the width of the conveyor belt.

The ribs or belt-like members are preferably integral with or bonded to the conveyor belts but they may be simply held in contact therewith.

The stiffening effect of the narrow belt-like members is especially advantageous when they are associated with the sealing belt or blanket of the developing section of the apparatus as such relatively rigid members disposed adjacent to the side edges of the said belt or blanket constrain it to lie closely adjacent to and in adequate sealing relationship with the surface of the developing tank or chamber.

Preferably the narrow ribs or belt-like members are of V section the wider fiat, top surface of which bears against or may be bonded to or formed integrally with, the inner surface of the sealing belt Or blanket adjacent to each side edge thereof and hold the side edges against the surface of the developing tank or chamber.

The V-shaped parts of the belts may be disposed in appropriately shaped slots provided for the purpose in the sealing belt rollers.

Preferably the inner surfaces of the conveyor belts are knurled, the outer surfaces in contact with the developing chamber or tank or with the printing cylinder or the like being plain and smooth.

The knurled inner surface of the belts ensures that the narrow belt-like members are either held in adequate 3 frictionalcontact with the said belts or that the said narrow belt-like members may be easily and readily bonded thereto.

The narrow belts are preferably so dimensioned and made of such material that the sealing belt or blanket is held firmly against the side edges of the developing tank or chamber.

Alternatively instead of providing separate belts to hold the side edges of the sealing belt or blanket in contact with the surface of the developing tank or chamber the inner surface, i.e. the surface not in contact with the developing chamber of the said sealing belt or blanket, may be provided with ribs adjacent to each side edge, such ribs travelling in slots provided for the purpose in the sealing blanket rollers and being sufficiently robust as to hold the edges of the sealing blanket against the developing tank surface along its edges.

If desired spring pressed rollers, appropriately grooved, and which may be rubber covered may be provided bearing on the inner surface of the sealing belt or blanket further to assist in holding the said sealing belt closely in contact with the face of the developing tank.

Such an arrangement is particularly advantageous where the developing tank is provided with an open face and an internal conveyor unit.

As a further alternative, the edge protuberances may be provided on the surface of the sealing belt or blanket in contact with the developing chamber, the developing chamber being provided with registering grooves, channels or trackways in which the protuberances are adapted to seat and move.

The grooves, channels or trackways provided on the developing tank surface are preferably disposed outside the zone of perforations, the protuberances on the sealing belt or blanket seating in the grooves, channels or trackways forming an effective seal to prevent escape of development vapours into the surrounding atmosphere.

The protuberances on the belts or bands maybe of any appropriate shape and may be formed on or attached in any convenient manner to the said belts or bands, for instance on the rubber sealing belt or band they may be moulded thereon during the process of manufacture of the said belt or band.

The grooves, channels or trackways on or in the rollers or tank surface may also be of any desired shape and may for instance be milled out of the metal surfaces or pressed thereon or alternatively, and particularly in the case of the developing tank-surface, prefabricated trackways may be affixed to, for instance by welding, the outer surface of the perforated wall of the said tank.

In a specific example of developing apparatus according to the present invention and described merely by way of example two narrow endless belts of approximately /a inch maximum width and madeof rubber or other flexible material are provided. The belts are-of V-section and of approximately /4 inch in depth, the V-portion of the belts being accommodated in grooves provided for the purpose in the sealing blanket rollers adjacent to their outer extremities. The belts ride in the grooves and are driven upon rotation of the sealing blanket rollers.

The invention will 'now be described with reference to the accompanying drawings which show by way of example several embodiments of apparatus according to the said invention.

In the drawings FIGURE 1 shows in section an embodiment of the present invention applied to the printing 'or exposure section of a diazotype or like photocopying apparatus.

which the material to be developed is traversed during the operation of the apparatus, and

FIGURES 4 and 5 show two dilferent arrangements of diazotype developing apparatus equipped with sealing arrangements and internal conveyors according to the invention.

FIG. 6 is a sectional view taken on the line 66 of FIG. 3.

Referring now to the drawings but first more particularly to FIGURES l and 2 the transparent printing cylinder of a diazotype or like photocopying machine is indicated at 1, a. source of actinic radiation (not shown) being disposed interiorly thereof.

The printing cylinder 1 extends for substantially the width of the machine and has lapped around a portion of its periphery the printer section narrow conveyor belts one of which is shown at 2 on the drawings.

The conveyor system, which as beforementioned comprises a plurality of such narrow endless belts, traverses an original to be copied together with the photosensitive material superposed thereon around the printing cylinder to effect exposure of the said material.

As shown on the drawing, the belts 2 are lapped around the printing cylinder 1 by means of rollers 3, 4, 5 and 6 the said rollers also extending for substantially the width of the machine and one of which is a driven roller traversing the belts 2 around the cylinder 1.

The rollers 3, 4, 5 and 6 are provided with a plurality of grooves 7, 8, 9 and 10 the number of grooves in each roller corresponding to the number of belts comprising the conveyor system.

Each belt 2 comprises an outer fabric surface 11 and an inner knurled or serrated surface 12 of rubber or like material and each is provided with a narrow belt-like member 13 of robust construction disposed centrally of the said belt and bearing on the inner, knurled, surface thereof.

The belt-like members 13 are each of V-section the fiat, wider, surface of the V bearing on or being bonded to the surface 12 of the belt 2, the members riding in the grooves 7, 8, 9 and 10, and being in driven engagement with the grooves in the driven roller.

It will be seen therefore that each belt 2 of the system is constrained by the belt members 13 and the grooves 7, 8, 9 and 10 provided in the rollers 3, 4, 5 and 6 to follow a correct track during its movement round the cylinder 1.

Referring now to FIGURE 3, a developing tank or chamber is shown at 14 and comprises a closed metallic member having a perforated surface 15 through which developing vapours emanate and come into contact with material to be developed as it is traversed over the perforated surface 15 by means of a wide endless moving sealing belt or blanket 16.

The belt or blanket 16 is preferably of rubber or rubberised fabric having a smooth surface 17 in contact with abnd sealing the perforated surface 15 of the tank or cham- The belt or blanket 16 is held in contact with surface 15 by means of guide rollers 18, 19 and 20 and tensioning roller 21 one of the guide rollers being a driven roller effective to move the belt or blanket 16 over the surface 15 of the developing tank or chamber 14.

It will be seen that by appropriately positioning rollers 18 and 20 it is a relatively easy matter to ensure that the blanket 16 effectively seals at the upper and lower ends of the developing chamber 14.

In accordance with this invention and to ensure adequate sealing of the blanket 16 along the side edges of the tank 14 a pair of narrow belt-like members one of which is shown at 22 are provided disposed adjacent to the side edges of the belt, respectively.

The belt-like members 22, which are similar to the member 13 above, bear on or are formed integrally with the inner surface 23 of the belt 16, which surface 23 is preferably kn'urled,and are accommodated in grooves 24,

25 and 26 provided for in rollers 18, 19 and 20 respectively.

The belt-like members 22, in bearing on the inner surface of the sealing blanket 16 adjacent to and coextensive with its side edges, hold the side edge portions of the said blanket 16 firmly in sealing relationship with the surfaces of the developing chamber 14 alongside the perforated surface 15.

Referring now to FIGURE of the drawings, which illustrates a diazotype apparatus of the kind using both internal and external conveyor belts, the developer tank 27 is provided with a rectangular or other shaped opening 28 in its front surface, the said opening 28 being closed or substantially closed by an internal conveyor belt 29 of vapour diffusing material. The conveyor belt 29 passes around guide rollers 30 and 31 one of which is a driven roller.

In addition to the guide rollers 30 and 31 a tensioning roller 33 is provided bearing against the inner surface of the conveyor belt 29 whereby it may be maintained at a desired appropriate tension.

The conveyor belt 29 is provided adjacent to each of its longitudinal side edges with belt-like members or p-rotuberant ribs one of which is indicated at 32 on the drawmg.

These belt-like members or ribs 32 ride in slots 34 and 35 formed for the purpose in the guide rollers 30 and 31 respectively.

Disposed over the open front face 28 of the developer tank 27 is the external sealing belt indicated at 36.

Belt 36 takes around appropriately disposed rollers 37, 38 and 39 and is provided with a tensioning roller 40 disposed against its outer surface.

The belt 36 is provided adjacent to each of its longitudinalside edges with belt-like members or ribs one of which is indicated at 41. These belt-like members or ribs ride in grooves 42, 43 and 44 provided for the purpose in rollers 37, 38 and 39 respectively as in the previous embodiments.

If desired spring pressed rollers 45 and 46 respectively may be provided bearing against the rear or inner surface of the belt 36 to hold it firmly in contact with the upper and lower ends of the developer tank 27.

The rollers 45 and 46, which bear on substantially the whole width of the belt 36, are provided with slots 47 and 48 respectively in which the belt-like members or ribs 41 ride.

The belt 29, as it passes over the aperture 28, is supported on a perforated plate 60 which constrains the belt to follow the curvature of the tank wall and also permits the ammonia vapour to penetrate through the belt. In an alternative arrangement both the belt 29 and the plate 60 are impervious and the outer face of the belt 29 is formed with recesses 01 pockets which hold sufficient ammonia gas for development.

Referring now to FIGURE 5 which shows a similar arrangement to that shown in FIGURE 4 and wherein like reference numerals indicate like parts on the drawing, the internal conveyor belt 29, which in this case is made of a chain mesh material, is disposed within the developer tank or chamber but arranged somewhat differently from the arrangement shown in FIGURE 3.

In this case the belt 29 in addition to taking around guide rollers 30 and 31 also takes around a roller 49, the narrow belt-like members or ribs 32 coextensive with the longitudinal side edges of the belt 29 riding in slots 34, 35 and 50 provided for the purpose in rollers 30, 31 and 49 respectively.

A tensioning roller 33 is also provided.

The external sealing belt 36 having integral with its longitudinal side edges the narrow belt-like members or ribs 41 is also arranged and disposed somewhat differently from the arrangement shown in FIGURE 3.

As shown, the belt 36 takes around guide rollers 37, 38, 39, 51 and 52 the members 41 riding in the slots 6 42, 43, 44, 53 and 54 respectively while tensioning rollers 40, 55 and 56 are provided effective to hold the belt 36 at the desired tension and to ensure that the members 41 are maintained in their slots during movement of the said belt 36.

I claim:

1. In photocopying apparatus for producing copies on light sensitive sheet material, a developing section including means for applying developer to light sensitive sheet material after exposure, continuous means in the developing section for supporting such sheet material during application of the developer and belt conveyor means for carrying light sensitive sheet material through the developing section, said conveyor means comprising a flexible belt and guide and driving means to cause the belt to travel over said sheet material supporting means with the sheets being processed held between the belt and the support means, said belt having longitudinally extending stiffening ribs for maintaining the belt in firm engagement with said sheet material supporting means.

2. Apparatus as claimed in claim 1 in which the ribs are on the face of the belt remote from the supporting means.

3. Apparatus as claimed in claim 1 in which the driving means comprise a driven roller having grooves to receive said ribs and to embrace the sides thereof in driving relation.

4. Apparatus as claimed in claim 1 in which the ribs are integral with the belt.

5. Apparatus as claimed in claim 4 in which the guide means comprise at least one roller having grooves in which the ribs are received.

6. Apparatus as claimed in claim 1 in which the ribs are on the face of the belt adjacent the supporting means and the supporting means have grooves in which the ribs are received.

7. Apparatus as claimed in claim 1 and having transverse spring-pressed rollers engaging the belt on the face remote from the sheet material, at the beginning and end of the developing sections and means underlying the sheet material opposite to the said rollers.

8. Apparatus as claimed in claim 1 in which the surface of the belt remote from the supporting means is knurled.

9. In photocopying apparatus for producing copies on light sensitive sheet material, a developing section including means for applying developer to light sensitive sheet material after exposure, continuous means in the developing section for supporting such sheet material during application of the developer and belt conveyor means for carrying light sensitive sheet material through the developing section, said conveyor means comprising a flexible belt and guide and driving means to cause the belt to travel over said sheet material supporting means with the sheets to be processed held between the belt and the sheet material supporting means, and means for pressing the edges of said belt firmly against the sheet material supporting means to hold sheet material being processed tightly against the said sheet material supporting means, which pressing means comprise narrow support belts running in engagement with the edge portions of the conveyor belt as it passes over the sheet material supporting means and on the face of the belt remote from the sheet material supporting means.

10. In photocopying apparatus for producing copies on light sensitive sheet material, a developing section comprising a chamber for containing gaseous developer and having an aperture in one wall, a perforate conveyor belt within the chamber and substantially covering said aperture, said conveyor belt having ribs along its side edges and at least one guide roller for said belt having grooves within which said ribs are received, and an external belt which covers said aperture and extends at its 7 side edges over the wall of the chamber along the sides of the aperture and has ribs along said side edges.

References Cited in the file of this patent 8 Wilson Nov. 25, 1941 Pratt et al. Nov. 5, 1946 Nassimbene Nov. 28, 1950 Trump Mar. 18, 1952 Dignan Oct. 22, 1957 Frantz May 26, 1959 

1. IN PHOTOCOPYING APPARATUS FOR PRODUCING COPIES ON LIGHT SENSITIVE SHEET MATERIAL, A DEVELOPING SECTION INCLUDING MEANS FOR APPLYING DEVELOPER TO LIGHT SENSITIVE SHEET MATERIAL AFTER EXPOSURE, CONTINUOUS MEANS IN THE DEVELOPING SECTION FOR SUPPORTING SUCH SHEET MATERIAL DURING APPLICATION OF THE DEVELOPER AND BELT CONVEYOR MEANS FOR CARRYING LIGHT SENSITIVE SHEET MATERIAL THROUGH THE DEVELOPING SECTION, SAID CONVEYOR MEANS COMPRISING A FLEXIBLE BELT AND GUIDE AND DRIVING MEANS TO CAUSE THE BELT TO TRAVEL OVER SAID SHEET MATERIAL SUPPORTING MEANS WITH THE SHEETS BEING PROCESSED HELD BETWEEN THE BELT AND THE SUPPORT MEANS, SAID BELT HAVING LONGITUDINALLY EXTENDING STIFFENING RIBS FOR MAINTAINING THE BELT IN FIRM ENGAGEMENT WITH SAID SHEET MATERIAL SUPPORTING MEANS. 